747-400D

The 747-400D is the 747 built for the shortest flights it ever made. “D” is for Domestic, and the aircraft was developed for Japanese trunk routes: sectors of an hour or two, flown constantly, with demand that justified the highest seat counts ever certified on the type.

It seats a maximum of 568 passengers in two classes, or 660 in a single class. Nineteen were built.

The winglets are missing — deliberately

This is the -400D’s signature, and it is the opposite of what most people assume. It lacks the wingtip extensions and winglets fitted to every other 747-400.

Winglets reduce induced drag, and on a long cruise that saves a great deal of fuel. But they also add weight and increase bending loads at the wing root — and on a one-hour sector, an aircraft spends most of its time climbing and descending rather than cruising. The fuel saved never repays the weight carried.

Removing them lowers wing stress, which matters enormously on an aircraft doing many takeoffs and landings a day. Cycles, not hours, are what wear out a domestic 747.

Other differences

• No extra fuel tanks. The -400D does not carry the additional tankage of the long-range versions; it does not need the range and the weight would be dead loss.
• More upper-deck windows than a standard -400 — two on the port side and four on the starboard side — reflecting the higher-density cabin above.
• Convertible back. A -400D could be converted to standard long-range configuration if an operator needed it, with the winglets and tankage fitted.

Service life

First flight	18 March 1991
Entered service	22 October 1991, Japan Airlines
Last delivery	December 1995, All Nippon Airways
Built	19

JAL retired its last -400D in 2011. ANA flew the type until 31 March 2014, when JA8961 made its final flight after 24 years and more than 33,000 cycles.

That cycle count is the whole story of the variant. A long-haul 747 of the same age might have accumulated a few thousand. These aircraft did the work of short-haul jets at 747 scale.

The idea has a long history

The -400D was the third generation of a Japanese domestic 747. The 747-100SR came first in 1973, with reinforced structure and reduced fuel; the 747-300SR followed with the stretched upper deck and 600-plus seats.